Texture is pinching and artifacting on the rounded edges of a mesh
Intro
Spheres can be generated with multiple approaches. Every approach has its down- and upsides. It depends what you are trying to achieve.

Sphere from Primitive Sphere
The problem here is the vertex on top. 
After applying subdivision you will get some interesting topology, looks cool but it's maybe not what you are looking for. I call it the tomato topology.


Sphere from Icosphere
Subdivision can be done while you enter parameters for the icosphere. There will not be a tomato topology. But there is a catch, you can't do loopcuts nor loopselections. Also it can cause problems if you use it with boolean modifier. Short: The triangle faces are causing issues down the line.


Sphere from Cube
With this approach you will be able to have quad topology without tomatos.
Loop selection is also possible.